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SunnyDays

ERA5 almanac — 8 years of real data

St. Augustine in September

St. Augustine in September is historically a poor month for sun: only 17% of days clear across 8 years (n=240, avg high 83°F). April is the clearest month for St. Augustine historically. Historical average, not a forecast.

What you are reading: 8-year historical averages from the ERA5 reanalysis, not a forecast. A month that is historically 90% clear can still be overcast on your specific trip. For this week’s actual forecast, see the live St. Augustine page. Both can be true at once: “historically strong in this month; this particular week is not.” We label which is which.

Early vs. Late September

Clear-sky percentage for St. Augustine in September, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early September
1st–15th		 11% n=120 83°F
Late September
16th–end		 23% n=120 83°F
Full month average 17% n=240 83°F

Bottom line

St. Augustine is a poor choice for sun in September: just 17% of days clear historically (n=240). April is the historically strongest month for sun here. The 8-year record is consistent — this is not a fluke bad stretch.

→ See all destinations in April — historically the best month for sun in St. Augustine.

Every month in St. Augustine

Compare across all months with data. Numbers are historical clear-sky %.

Historical clear-sky % for St. Augustine, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 9% n=248 All destinations →
February 22% n=226 All destinations →
March 25% n=248 All destinations →
April 42% n=240 All destinations →
May 40% n=248 All destinations →
June 14% n=240 All destinations →
July 9% n=248 All destinations →
August 6% n=248 All destinations →
September ← this page 17% n=240 All destinations →
October 34% n=248 All destinations →
November 23% n=240 All destinations →
December 13% n=248 All destinations →

All percentages are historical averages from the ERA5 reanalysis via Open-Meteo, 8 full years (2018–2025). “Clear” means avg high ≥ 72 °F, precipitation < 1 mm, and a non-precipitation weather code. This is history, not a forecast. The live 7-day outlook for any destination is on its own page and may differ from the long-run average. Data from Open-Meteo.